Lu (hey - this is getting personal) : I don't see the point in you taking the time to ask the manufacturer of WD40 "Is it safe to use on rotor blades?"
What type of blades ? What construction ? What materials ? etc. etc.
From your other postings on pprune I'm guessing that you are either an engineer or think you are an engineer.
So why ask such a wide-ranging, non-specific, non-engineering question ?
If you think there's a problem - email your concerns to Pat Cox. But for hell's sake please don't post suppositions and half-truths. Who are you trying to impress ?
If Robinson's engineer can stand in front of a professional pilots' class and recommend a procedure, then we have to accept that he knows what he is saying is correct.
You should get a job.